Installing Windows 10 on iMac

[colinwebb]

I’ve been going around in circles trying to install Windows 10 on my IMac. The reason I want to do this is because I have an excellent scanner that can’t be used on Mojave OS. My set up is as follows I have an external 1tb SSD with Mojave installed on it and for Time Machine backups I use an external NAS. This leaves me with an internal drive of 1tb where I would like to install W10. Boot camp assistant doesn’t function telling me to remove external storage but what? This led me to create a Windows 10 USB installation and format my internal drive to NTFS ready to install. This is where it stalls with various messages the latest being can’t find an existing partition or create a new one, even though I’ve supposedly already done that.

 

[allan.nyholm]

I have the same issue when I want to use Bootcamp to install Windows 10 on my iMac with an external SSD on Thunderbolt.

My solution:
Disconnect your SSD and any other physical external drives upon/after rebooting your iMac and at the EFI boot page.

Usually I create the USB for Windows 10 and when Windows is in its initial stage press Shift+F10 (also using the Fn-key if you use a wireless Apple keyboard)

This leads you into the Command Line interface and you then you type the following 'diskpart' -> 'list disk' now you should locate your largest drive at the 1TB mark (usually its disk 0(zero)) -> 'select disk 0' -> 'clean' -> 'convert gpt'

type once more 'list disk' after the last entry above and see that your internal 1TB drive is indeed GPT formated.

type 'exit' 2 times to exit the Command Line interface or just close the Command Line interface window by pressing the close button.

Next you proceed installing Windows 10 by going through the usual steps. When you arrive at the dialogue window on where to install Windows 10 you can select the drive you just formated and proceed from there. No need to reformat in the install dialogue window - only click to continue using the drive. Windows 10 will create the partitions it needs for it to function.

 

[Woof Woof]

Before fighting with windows to get your scanner to work, have you checked out vuescan to see if your scanner is supported? It is my goto for using oddball scanners on the Mac.

https://www.hamrick.com/vuescan/supported-scanners.html (Scroll down the page to see if you can find your scanner brand, and after clicking the brand, scroll down to the bottom of the page to see the models.)